Air heater



Sept. 9, 1930. e. H. PHELPS ET AL AIR HEATER Filed Oct. 19, 1928 5 Sheets-Sheet 1 J7 ii EN TOR. J 20 was urrm fie o/ ge HP/wZ s.

TTORNEY /W%//% Sept. 9, 1930. PHELPS ET AL 1,775,173

AIR HEATER Filed Oct. 19, 1928 3 Sheets-Sheet 2 31/ B GeorgeHP/reZ/vs. ,2 Mfidwomvn Sept. 9, 1930. PHELPS ET AL 1,775,173

AIR HEATER Filed 06";- 19, 1928 3 Sheets-Sheet 3 INVENTORS 7/? 00am 1,. Ala/ray, J7 (kw/ye HFVIeZ JS ATTORNEY mitting it to Patented Sept. 9, 1930 UNITED STATES PATENT OFFICE GEORGE E. P HELPS, OF WAREHOUSE POINT, CONNECTICUT, AND THOMAS E. MURRAY, m, BROOKLYN, NEW YORK, ASSIGNOBS, BY DIRECT AND MESNE ASSIGNMENTS,

TO METROPOLITAN ENGINEERING COMPANY, A CORPORATION OF NEW YORK am HEATER Application filed October 19, 1928. Serial No. 313,474.

In certain previous applications we have described a ty e of radiators in which corrugated sheets of thin metal, copper preferably, are applied to a pipe or chamber for steam or 6 hot water or to an electric heating element and from flues and passages in which the air is heated and rises and is circulated throughout the room to be heated. Such radiators have a high efficiency and can be $9 manufactured economically. Similarprinci- I les. are employed according to the present invention, using a hot gas as the heating me- 'dium. The accompanying drawings illustrate embodiments of the invention.

Fig. 1 is a perspective view omitting the casing. 1 Fig. 2 is a plan of the heater located in a fireplace. Fig. 3 is a perspective of the same arranged 2 for connection to a discharge pipe for the used gas.

Fig. 4 isan end elevation of a modification. Fig. 5 is a side elevation of the heater of Fi 4 mounted for use. ig. 6 is a perspective of the interiorof a modified type. v

Fig. 7 is a rear elevation of a slightly different construction.

Fig. 8 is an enlarged detail. ig. 9 is a rear elevation of a modification.

'Where steam or hot water is used for the heating medium as in previous applications, it is sufiicient to use a comparativel small tube or vessel therefor. But for eflicient use of gas it should be brought into contact with a larger surface. For this purpose a corrugated sheet of thin copper or an equivalent arrangement of fins on large area is provlded for abstractin heat from the gas and transt .6 extended surface of flues or fins forming the air passages.

' The two extended area structures are mounted on opposite sides of a plate 1 of thin sheet copper. Other metals may be used for this late as well as other parts of the heater. 8n the outer face of the plate 1 (see Fig. 8) is a-sheet corrugated to form yertical fins 2 connected at their alternate outer edges by plates 3 and at their inner edges by plates 4 so as to form vertical flues 5 which are closed in cross-section and passages 6 which are closed on three sides but open at the outer side.

fins 7 connected by plates 8 and 9 to form closed flues 10 and channels 11.

The air circulating and heating-structure is indicated as a whole by the numeral 12, and the gas heated structure by the numeral 13. The latter is made somewhat shorter than the former to allow space above for passage of the exhaust gas to an escape flue and at the bottom for an inlet for hot gas if such gas be .brou ht from a distant source. 'The a a- 9g PP ratu is designed for use however with a burner consisting of a pipe 14 applied directly beneath the heating passages and perforated at intervals along the top forignition of the gas. The parts may be united in various ways as for example by welding the parts 4 and 9 together through the plate 1, as indicated at 49 in Fig. 8; or by means of straps applied to opposite sides of .the registering plates 4 and 9 and welded to "each other at intervals.

through these 1, as describe plications.

Fig. 2 shows the structure of Fig. 1 set in the face of the fireplace 15, with the plate 1 substantially flush with the inner face of the wall 16. The burnt gas will thus pass up the chimney, and the air will be heated and circulated through the room. -According to Fig. 3 the heating lates and the supporting plate in detail in our previous apas side of the radiating structure is enclosed by a face plate 17 and side plates 18 and a to plate 19 attached as shown to the edges of t The casing is open or perforated at the bottom to admit air foricombustion and communicates at the top with an outlet pipe 20.

Fig. 4 illustrates a design in which there are two units like that of Fig. 1 with the On the back face of the plate 1 is a: similar-sheet of corrugated metal providing e supporting plate 1.

corrugated plates 13 placed back to'back. I I

The whole may be mounted on a wall or supported on legs, and the same is true of all the other desi ns illustrated.

Fig. 5 i ustrates a suitable arrangement of flues and connections for use where there is no chimney convenient. Below the burner 14 there is a manifold 21from which air may pass through adamper or regulating device A v 22 to the burner above.

An inlet line 23 conducts fresh air to the manifold. From the space above the gas passages-an outlet pipe' 24 carries off the burnt gases. A box 25 with a longitudinal partition 26 dividing it into two horizontal passages extends through the wall 27. The passages communicatewith the air inlet 23 and the gas outlet 24: respectively.

3 This makes the blowing out of the flame extremely unlikely. Also it prevents any burned or-unburned gas from escaping into the room since the flame and combustion space are entirely cut off from the room and are open only to the outside air. Many variatlons of the structure can be designed which will cause any wind, or pressure from the outside air to be substantially equal in both the flues.

Air and gas connections as described may 'be used with any of the heaters referred to herein.

According to Fig. 6 the fins or corrugated structure 28 for contact with the gas-are arranged horizontally. The burner in this case will be mounted to supply the heating gas at one side and the flue arranged to take it off at the opposite side. 1 i i Fig. 7 shows a modification of this idea in whichbafiles 29 at one side are staggered with respect to baflies 30 at the .0pp0site side. Theheating gas may be supplied from a remote source or from a burner in the bottom and will take the sinuous course indicated by the dotted lines '31, escaping at the top. The casing, and the arrangements for admitting air and exhausting burnt gas are substan:

tially the same for Figsfti and 7 as for the other figures. .The welding connections are similar to those in Fig. 8, the welds being made where the horizontal straps and plates at one slde of the support 1 cross the vertical straps and plates at the other side- Where a heater of considerable length and capacity is desired, the arrangement of Fig.

9 is preferable. Roughly speaking it duplicates the corrugated plates 28 of Fig. 7 on the gas side of the intermediate plate 1. By

arranging the fins in two separate sets in this way, the paths of the gases are kept com-' paratively short. Whereextra long passages are provided there is a tendency for the lowermost passages to-become overheated compared with those above it. This is avoided by the two units of Fig. 9 placed end to end, with the hot gas divided into two streams of half length and of opposite directions as indi-, cated by the arrows.

-. previously through the first pass.

The term extended area structure is used to define a structure which is corrugated, finned or similarly shaped so as to present a surface which is materially greater than the. area of a flat projection of the structure; thus providing a comparatively large contact surface with air or gas within a limited space or rectilinear distance. 1 I A heater as long as that ofFig. 9 has twice the capacity, but has the same'length of' travel of the hot gas in each pass as -in the case of Fig. 7. To further reduce overheating of the bottom fin, the bottom center'bafile 29 has openings 32 through it which allow. part of the gas to pass directly to the second pass ofthe heater, that is without going A heater of greater length and hot gas units 28 can be made in the same way, the only additional requirements being amanifold outletto bring the discharge gases together and lead them toa common flue.

The plate which separates theair from the gasis not necessarily a fiat plate as illustrated. It'may, for example, be corrugated to provide channels for the air 'on'one side and the gas on the other. .JAlso the shape and construction of the extended area structures for the gas and for the air may be varied in a number of ways.

The walls of the passagesare formed in part by the intermediate plate so that the latter is heated on one side directly by con'- tact with the gas and also by conduction from the other walls of the passages, and at the other side the air is heated" directly by con tact with the. plate as well as by contact with the remaining walls of theair passages. The area of contact with the air'is greater than that of contact with the heating gases.

" This makes for efficiency; the air extracting the heat practically to the limit of the distance to which it can be conducted through the metal p Various modifications may be made by those skilled in the art without departing from the invention as defined in the following claims.

What we claim is:

'1. An air heater comprising a plate, yertical fins on one face ofsaid plate-formingvertical fiues for heating air and inducing a L strong upward draft of such heated air and fins on the opposite side of the plate forming passages for a heating gasthe fins at the opposite/ sides being unitedflto each other through the plate. y

2. An air heater comprising a supporting plate, a corrugated plate applied to one facethereof with the corrugations vertical sons to heat the air and induce a rapid upward draft of air and a corrugated plate applied to the opposite side of the supporting plate a transmit heat througli the supporting plate to the opposite corrugated plate.

3. An air heater comprisin a plate of conducting metal at one side of w ich are a number of parallel passages for a hot gas, means for supplying hot gas to said passages, the

v walls of said passages being formed in part tical fins on one face of said plate forming by said plate so that thelatter is heated di:

rectly on one side by contact with the gas .andalso by conduction from the remaining walls of said passages, and at the other side of which are slmilar passages through which the air to be heated is caused to ass, the walls of which are formed in part y said plate so that the air is heated directly by contact therewith and also by contactwiththe remaining walls of said passages.

4. An air-heater comprlsing aplate of con- J ductive metal at each side of which are a number of parallelpassages for a hot gas and for the air to be heated respectively, means for supplying hot gas to the passages at one side for causingthe air to be heated to pass through the passages at the other side, the area of contact of the air being substantially' greater than that of the hot gas.

5. An air heater comprising a plate, verleading from the heater to t e outer air at Y signed our names.

points closely adjacent to each other so as to maintain approximate equilibrium of pressures'in said pipes.

In witness whereof, we have hereunto GEORGE H. PHELPS. THOMAS E. MURRAY, JR. 

